Bats are abundant and effective seed dispersers inside the forest, but what happens when a forest is fragmented and transformed into pasture? The landscape at Los Tuxtlas, Mexico, originally rainforest, is greatly fragmented and covered with pastures. We analyzed the seed rains produced by frugivorous bats and birds under isolated trees in pastures in the fragmented landscape and the contribution of this process to vegetational recovery. We surveyed bats and obtained fecal samples under isolated trees in pastures. We also collected seed rain below the canopy of 10 isolated Ficus trees, separating nocturnally dispersed seeds from diurnally dispersed seeds. We caught 652 bats of 20 species; 83% of captures were frugivores. The most abundant species were Sturnira lilium (48%), Artibeus jamaicensis (18%), Carollia perspicillata (12%), and Dermanura tolteca (11%). Fecal samples contained seeds of 19 species in several families: Piperaceae (50%), Moraceae (25%), Solanaceae (12%), Cecropiaceae (10%), and others (3%). Sturnira lilium was the most important disperser bat in pastures. Seed rain was dominated by zoochorous species (89%). We found seed diversity between day and night seed captures to be comparable, but we found a significant interaction of disperser type ( bird or bat) with season. Seven plant species accounted for 79% of the seed rain: Piper auritum (23%), Ficus ( hemiepiphytic-strangler tree) spp. (17%), Cecropia obtusifolia (10%), P. amalago (10%), Ficus ( free-standing tree) spp. (8%), P. yzabalanum (6%), and Solanum rudepanum (5%). Bats and birds are important seed dispersers in pastures because they disperse seeds of pioneer and primary species (trees, shrubs, herbs, and epiphytes), connect forest fragments, and maintain plant diversity. Consequently, they might contribute to the recovery of woody vegetation in disturbed areas in tropical humid forests. tantes dispersores en pastizales ya que dispersan semillas de especies pioneras y primarias (árboles, arbustos, hierbas y epífitas); conectan remanentes de selva y mantienen la diversidad vegetal. Consecuentemente pueden promover la recuperación de la vegetación leñosa en áreas perturbadas de regiones tropicales húmedas.

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Abstract. Large isolated trees are a common feature of the agricultural landscape in humid tropical regions originally covered by rain forest. These isolated trees are primarily used as a source of shade for cattle and people. 13 pastures (totalling ca. 80 ha) currently used as cattle pasture were studied. In them, we registered 265 isolated trees belonging to 57 species. 50 trees of the most frequent species (Ficus spp. n = 30 and Nectandra ambigens n = 20) were selected to examine the influence of isolated trees on floristic composition and vegetation structure in the pastures. At each tree, three 4–m2 quadrats were sampled: under the canopy, directly under the canopy perimeter, and beyond the canopy in the open pasture. Under‐canopy vegetation was structurally and floristically different from the other two sampling sites. Mean species richness per quadrat was significantly higher under the canopy (17.8 ± 4.3 SD) than at the canopy perimeter (11.2 ± 3.4) and in the open pasture (10.6 ± 3.6) sites. Stem density was higher at under‐canopy sites, where greater proportions of endozoochorous and rain‐forest species were found. Isolated trees function as nursery plants for rain‐forest species by facilitating the establishment of zoochorous species whose seeds are deposited under the tree canopies by frugivorous birds or bats. Our results imply that isolated trees may play a major role in seed dispersal and establishment of native species, which is of consequence for the preservation of rain‐forest species in these fragmented landscapes.